Hydrocephalus

September, 2005

What is Hydrocephalus?

The term
hydrocephalus is derived from two words: "hydro" meaning water, and
"cephalus" referring to the head.

Hydrocephalus is a condition in which excess cerebrospinal fluid
(CSF) builds up within the ventricles (fluid-containing cavities) of the
brain and may increase pressure within the head. Although hydrocephalus
is often described as "water on the brain," the "water" is actually
CSF, a clear fluid surrounding the brain and spinal cord. CSF has three
crucial functions: 1) it acts as a "shock absorber" for the brain and
spinal cord; 2) it acts as a vehicle for delivering nutrients to the
brain and removing waste; and 3) it flows between the cranium and spine
to regulate changes in pressure within the brain. Hydrocephalus can
occur at any age, but is most common in infants and adults age 60 and
older. According to the National Institute of Neurological Disorders and
Stroke, hydrocephalus is believed to affect approximately one in every
500 children. The majority of these cases are often diagnosed before
birth, at the time of delivery, or in early childhood.

Common Causes of Hydrocephalus

Although rare, hydrocephalus can be inherited genetically or may
be associated with developmental disorders, including spina bifida
(congenital defect of the spine) and encephalocele (hernia of the
brain). Other causes can include bleeding within the brain, brain
tumors, head injuries, complications of premature birth such as
hemorrhage, or diseases such as meningitis or other infections. In some
cases, normal flow of CSF within the brain is blocked, resulting in
fluid build-up.

Symptoms of hydrocephalus vary greatly from person to person.
According to the Hydrocephalus Association, some of the most common
symptoms are listed below as a reference.

Symptoms of Hydrocephalus in young and middle-aged
adultsHeadache; difficulty in remaining awake or waking up; loss
of coordination or balance; bladder control problems; impaired vision
and cognitive skills that may affect job performance and personal
skills.

Symptoms of Hydrocephalus in older adultsLoss
of coordination or balance; shuffling gait, memory loss; headache; or
bladder control problems. Hydrocephalus is often categorized for age
groups as either congenital or normal pressure hydrocephalus. Congenital
hydrocephalus refers to conditions that are caused by conditions
existing at birth. Primary symptoms include headache, nausea, vomiting
and drowsiness. Normal pressure hydrocephalus (NPH) is the accumulation
of cerebrospinal fluid that causes the ventricles in the brain to become
enlarged, with little or no increase in pressure. Adult-onset NPH
mainly occurs in adults age 60 and older. Patients with NPH often get
misdiagnosed with Alzheimer’s disease or dementia, as some of the
symptoms mimic these two conditions.

Diagnosing Hydrocephalus

Before
your doctor can recommend a course of treatment, he or she will:

Review
your medical history, and perform a physical examination

Perform
a complete neurological examination including diagnostic testing if
needed

Ask specific questions to determine if symptoms are
caused by hydrocephalus

The neurological examination
will also help to determine the severity of your condition. Further
tests such as an ultrasound (if the patient is an infant), computed
tomography (CT or CAT scan), or magnetic resonance imaging (MRI) may be
ordered. The tests may reveal useful information about the severity of
the condition and its likely cause.

When Surgery is Necessary

Hydrocephalus
can be treated in a variety of ways. The problem area may be treated
directly (by removing the cause of CSF obstruction), or indirectly (by
diverting the fluid to somewhere else; typically to another body
cavity). Indirect treatment is performed by implanting a device known as
a shunt to divert the excess CSF away from the brain. The body cavity
in which the CSF is diverted is usually the peritoneal cavity (the area
surrounding the abdominal organs).

In some cases, two procedures
are performed, one to divert the CSF, and another at a later stage to
remove the cause of obstruction (e.g., a brain tumor). Once inserted,
the shunt system usually remains in place for the duration of a
patient's life (although additional operations to revise the shunt
system are sometimes needed). The shunt system continuously performs its
function of diverting the CSF away from the brain, thereby keeping the
intracranial pressure within normal limits.

An alternative
operation called endoscopic third ventriculostomy utilizes a tiny camera
to look inside the ventricles, allowing the surgeon to create a new
pathway through which CSF can flow.

Recovery

Your
neurological function will be evaluated post surgery. If any
neurological problems persist, rehabilitation may be required to further
your improvement. However, recovery may be limited by the extent of the
damage already caused by the hydrocephalus and by your brain's ability
to heal.

Because hydrocephalus is an ongoing condition, long-term
follow-up by a doctor is required. Follow-up diagnostic tests including
CT scans, MRIs and x-rays, are helpful in determining if the shunt is
working properly. Do not hesitate to contact your physician if you
experience any of the following postoperative symptoms:

Redness,
tenderness, pain or swelling of the skin along the length of the tube
or incision

Irritability or drowsiness

Nausea,
vomiting, headache or double vision

Fever

Abdominal
pain

Return of preoperative neurological symptoms

Prognosis

The
prognosis for hydrocephalus depends on the cause, the extent of
symptoms, and the timeliness of diagnosis and treatment. Some patients
show a dramatic improvement with treatment while others do not. In some
instances of NPH, dementia can be reversed by shunt placement. Other
symptoms such as headaches may disappear almost immediately if the
symptoms are related to elevated pressure.

In general, the earlier
hydrocephalus is diagnosed, the better the chance for successful
treatment. The longer the symptoms have been present, the less likely it
is that treatment will be successful. Unfortunately, there is no way to
accurately predict how successful surgery will be for each individual.
Some patients will improve dramatically while others will reach a
plateau or decline after a few months.

Shunt malfunction or
failure may occur. The valve can become clogged or the pressure in the
shunt may not match the needs of the patient, requiring additional
surgery. In the event of an infection, antibiotic therapy may be needed.
A shunt malfunction may be indicated by headaches, vision problems,
irritability, fatigue, personality change, loss of coordination,
difficulty in waking up or staying awake, a return of walking
difficulties, mild dementia or incontinence. Fortunately, most
complications can be dealt with successfully.